Electric power transmission tower



Jan. 10, 1939. B OBBARD 2,143,612

I ON TOWER Filed Oct. 51, 1936 [0 2/0 .Fgj, Z

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INVEN TOR. NOE/Wfl/N 5. 055450,

- M WM H/S A TTORNEYS.

Patented J... 10, 1939 ELECTRIC POWER. TRANSMISSION TOWER Norman B.Obbard, Sewickley, Pa. Application October 31, 1936, Serial No. 108,663

2 Claims. (Cl. 189-22) UNITED STATES PATENT OFFICE This inventionrelates to towers for suspending wires and is particularly concernedwith electric power transmission tower ground wire peaks, one of theobjects being to provide a construction whereby the longitudinal wirepull is transmitted properly to the legs of the tower but adapted toaccommodate the same.

Specific examples of the present invention are illustrated by theaccompanying drawing, in which:

Figure 1 is a perspective of an electric power transmission line, thetowers of which embody the features of the present invention.

Figures 2 and 3 are diagrammatic views representing two possible ways ofconstructing the ground wire peaks of a transmission tower to embody thefeatures of the present invention, the tower as shown by Figure 1 havingits peaks constructed according to the diagrammatic showing of Figure 3.

The drawing illustrates a tower having two of its legs I alignedparallel the ground wires 2 of the transmission line, the whichtherefore constitute a set of legs particularly well adapted toaccommodate the longitudinal pull of these wires. Members 3 spreadupwardly from this set of legs I and, in conjunction with other members,support a superstructure 4 designed to distributively transmit thevertical and transverse wire loads to all of the legs of the tower, itbeing understood that the other two legs of the tower also support thissuperstructure through the members 3.

This superstructure includes members 5 that are equally spaced on bothsides of the towers center line and are aligned parallel with thelongitudinal wire load. These members form continuations of the members3 and are intended to transmit the longitudinal wire load to the legs Iof the tower. However, conventional peak constructions are such that thelongitudinal wire pull is transmitted to other parts of thesuperstructure so as to put the latter under a twisting stress. This isundesirable.

According to the present invention, the peak is in the form of a tripodextending from the superstructure 4 and having two of its legs 6 alignedparallel with the longitudinal wire load and connecting directly withthe members 5 of the superstructure. The apex of this peak is arrangedin the center line of the tower. The third leg I of the tripod extendstransversely of the ground wire. and is connected with thesuperstructure 4 at the center line of the tower.

In the first example of the invention the superstructure 4 is in theform of a rectangular girder,

and this third leg I is connected to a member 8 arranged transversely ofthe superstructure.

In the second example of the invention the superstructure is in the formof a triangular girder having a member 9 arranged in the center line ofthe tower, and it is therefore only necessary to connect the leg I tothis memberv 9. The apex II] of the peak is in each instance adapted tocarry the ground wire 2 of the transmission line. 10

The transverse and vertical wire loads are transmitted by all of thelegs of the tripod, that is to say, the legs 6 and I, to thesuperstructure 4 whereby the latter may distribute it to all of the legsof the tower and to the tower structure as a whole. However, due to theleg I of the peak being connected to the tower at the latters centerline, the longitudinal wire load can be transmitted only through themembers 5 of the superstructure and, by way of the members 3 to the legsI which are aligned parallel with the ground wires and are, therefore,best adapted to accommodate this load.

It is to be understood that a ground wire peak is different from ahorizontal arm of triangular or other form. In the latter two legs maybe aligned parallel with the longitudinal wire load but since the legsare in a plane at right angles, or nearly so, with any legs that mayalso be so aligned, the entire reaction is one of torque. To involve theproblem solved by the present invention two of the peak legs must notonly be alignedas mentioned but they must also be in a plane at leastapproximately parallel with the plane of the tower legs that are also soaligned. 3

I claim:

1. A wire suspension tower including legs for carrying all of the wireloads, a superstructure supported by said legs for distributivelytransmitting the vertical and transverse wire loads to the latter, saidsuperstructure including members equally spaced on both sides of thetowers center line in alignment parallel with the longitudinal wire loadand connecting with a set of said legs aligned with the longitudinalwire load for transmitting the latter to said set of legs, and a tripodextending upwardly from said superstructure for supporting a wire fromits apex, the latter being in the transverse center line of the towerand two of the legs of said tripod being aligned parallel with thelongitudinal wire load and connecting with said members while the thirdleg extends transversely and connects with said superstructure in thetransverse center line of the tower, whereby the longitudinal wire loadis transmitted as through the first named legs of said tripod throughsaid members and so primarily to said set of tower legs while thevertical and transverse wire loads are transmitted to the legs of saidtower by distribution through said superstructure.

2. An electric power transmission tower including main legs of which twoare aligned parallel with the transmission line, a superstructuresupported by said legs, and a tripod extending upwardly from saidsuperstructure with two of its legs aligned parallel with said line in aplane at least approximately parallel the plane of said two main legsand with its third leg connecting with said superstructure at thetransverse center line of the tower, the peak of said tripod beingadapted to support a wire extending parallel with the transmission lineand said two main legs and said, two tripod legs interconnecting so asto transmit stresses at least approximately straight from the latterthrough the former to the ground. 10

NORMAN B. OBBARD.

